NaR is an enzyme, which is a biological compound. It is nontoxic and 100% safe for humans, since it is an enzyme that we encounter everyday. NADH is a B vitamin derivative. This makes our kits safe for the environment, disposal of the kit reagents will do no harm. Click here to article: USGS Methods of the National Water Quality Laboratory. 2011. PDF (3)


NaR purified from corn leaves (NaR, E.C. 1.6.6.1),  as a replacement for toxic cadmium, has proven to be a reagent of choice for routine photometric and colorimetric determination of nitrate. Click here to article: Environmental Science and Technology, 2002 PDF (4) 


The advantages of corn NaR include: 1) high purity, 2) fast reaction time, 3) high selectivity for nitrate, 4) simple reaction conditions, 5) no hazardous reagents needed. Click here to article: Environmental Science and Technology, 2002 PDF (4)


The NaR-based nitrate assay offers excellent recovery, or efficiency of conversion, of nitrate to nitrite. Conversion efficiency of NaR approaches 90%. This is an improvement over the cadmium (Cd) or zinc (Zn) method. Click here to article: Air &  Waste Management Association Proceedings, 1997. PDF (1)


Comparison of the enzyme-based method with the Cd kits, Zn kits and with the Thermo Scientific™ Orion™ Ion Selective Electrode (ISE) nitrate test, the NaR method shows greater sensitivity in the low ranges, and is more consistent with the ISE values in all of the samples tested. Click here to article: Air &  Waste Management Association Proceedings, 1997. PDF (1)


Enzyme based assays in general are less subject to interference or false positives than more conventional techniques such as ion selective electrodes. Click here to article: Air &  Waste Management Association Proceedings, 1997. PDF (1) 


The NaR reduces nitrate to nitrite with specific­ity exceeding that of copperized cadmium and is nontoxic. Click here to article: USGS Scientific Investigations Report 2013-5033. PDF (2) 


Recombinant Arabidopsis nitrate reductase, expressed in the methylotrophic yeast Pichia pastoris, is a highly effective catalyst for nitrate analysis at 37°C. Recombinant production of enzyme ensures consistent quality and provides means to meet the needs of environmental chemistry. Click here to article: USGS Scientific Investigations Report 2013-5033. PDF (2)


The electron donor for our enzyme is more cost effective. Our form of Nitrate Reductase, specifically, compared to competitors' enzyme, uses NADH rather than the more expensive NADPH. Click here to article:  USGS Methods of the National Water Quality Laboratory. 2011. PDF (3)


References:

  1. Campbell E.R., Corrigan J.S., Campbell, W.H., Field Determination of Nitrate using Nitrate Reductase, Field Analytical Methods for Hazardous Wastes and Toxic Chemicals. Air & Waste Management Association, 1997: pp. 851-860, Pittsburgh PA
  2. Patton, C.J., Kryskalla, J.R., U.S. Geological Survey Office of Water Quality, National Water Quality Laboratory Analytical,  Properties of Some Commercially Available Nitrate Reductase Enzymes Evaluated as Replacements for Cadmium in Automated, Semiautomated, and Manual Colorimetric Methods for Determination of Nitrate Plus, Nitrite in Water: Scientific Investigations Report 2013–5033: Page 2
  3. Campbell, W.H., Song, P., Barbier, G.G., Nitrate reductase for nitrate analysis in water, Environmental Chemistry Letters, June 2006, Volume 4, Issue 2, pp 69-73 
  4. Patton C.J., Fischer, A.E., Campbell, W.H., and Campbell, E.R.. Corn leaf nitrate reductase: A nontoxic alternative to cadmium for photometric nitrate determinations in water samples by air-segmented continuous-flow analysis, 2002, Environmental Science and Technology, 36: 729-35.  

Above information is courtesy of NECi (The Nitrate Elimination Company, Inc.)